Network service header (nsh) metadata-based end-to-end multimedia session identification and multimedia service optimization

ABSTRACT

A classifier node in a service function chaining system receives a media stream from an endpoint device. The media stream is associated with a media session between the endpoint and at least one other endpoint. The classifier node determines a service function path for the media stream. The service function path includes an ordered list of service functions to process the media stream. The classifier node determines a session identifier for the media stream and encapsulates the media stream with a Network Service Header. The Network Service Header includes an indication of the service function path and a metadata header with the session identifier.

TECHNICAL FIELD

The present disclosure relates to applying service function chains in networks.

BACKGROUND

Service Function Chaining enables virtualized networking functions to be implemented as part of a cloud network. A Service Function Chain defines an ordered list of a plurality of service functions (e.g., firewall, compression, intrusion detection/prevention, load balancing, etc.) that may be applied to packet flows in the network. A flow enters the network through a classifier node that generates a Service Function Path for that flow according to the Service Function Chain policy. The classifier node encapsulates each packet of the flow with a Network Service Header that indicates the service functions to which the flow will be subjected, and the order the service functions will be applied.

Service Function Chaining and Network Service Headers provide a scalable, extensible, and standardized way of sharing metadata between both network nodes and service nodes within a network topology. This allows for disparate nodes that require shared context, but do not communicate directly, to share that context via metadata within the packets traversing the network or service topology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system block diagram showing a Service Function Chain network environment for use with media sessions, according to an example embodiment.

FIG. 2 is a simplified block diagram of a classifier network element within the Service Function Chain network environment, according to an example embodiment.

FIG. 3 is a system block diagram showing a classifier node initiating a media session between two endpoints, according to an example embodiment.

FIG. 4 is a system block diagram showing a classifier node using session identifier metadata to direct different media streams, according to an example embodiment.

FIG. 5 is a flowchart showing the operations of a classifier node encapsulating a flow with a Network Service Header including session identifier information, according to an example embodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

A classifier network device receives a media stream from a first endpoint device. The media stream is associated with a media session between the first endpoint device and at least a second endpoint device. The classifier network device determines a service function path for the media stream. The service function path includes an ordered list of service functions to process the media stream. The classifier network device determines a session identifier for the media session and encapsulates the media stream with a Network Service Header. The Network Service Header comprises an indication of the service function path and a metadata header with the session identifier. The classifier network device may be a physical device or a virtual device (software running on a compute node to perform functions of a physical network device).

Example Embodiments

When media streams traverse through a Service Function Chain domain, various service functions in a Service Function Path may use a mechanism to identify media streams associated with a particular media session useful. Identifying media streams may be useful for the purposes of session correlation (e.g., session recording), debugging/troubleshooting, session tracking, multimedia service optimization, among other purposes. All functions in such a deployment (e.g., a conferencing server, a recording server, a session border controller, a compressor, a logger, etc.) may be individual service functions in the Service Function Chain domain. Techniques presented herein provide for using the Network Service Header in the Service Function Chain domain to propagate a session identifier across the Service Function Chain domain in order to facilitate media session identification, correlation, and intelligent application services to the media streams.

One session identifier (ID) used in end-to-end multimedia session identification is the Session-ID, such as in the Session Initiation Protocol (SIP) and the H.323 protocol. The Session-ID may be used for a variety of supplementary services, such as call transfer, conferencing and SIP session recording. Carrying the end-to-end session identifier, such as the Session-ID, in the Network Service Header metadata to various multimedia service functions (e.g., Session Border Control/Back-to-back User Agents, SIP proxy, conferencing server, session recording server, transcoding server, etc.) enables identification, tracing, and correlation of signaling and media sessions.

In addition to troubleshooting and tracing, carrying the session identifier in the Network Service Header metadata enables making service function decisions and branching based on the session identifier. For example, selective session recording may be achieved by looking at the session identifier in the Network Service Header and dynamically directing the relevant streams to the session recoding service function.

The application of service functions to a given media stream based on a session identifier in the Network Service Header may be applied to multimedia protocols and supplementary services that have already implemented Session-ID, as well as those that have not yet implemented the Session-ID and may act as a way to accelerate end-to-end Session-ID development and deployment in a service chain scenario, without need for any type of deep packet inspection.

Referring now to FIG. 1, a simplified block diagram of a media-session-aware Service Function Chaining system 100 is shown. An endpoint 110 configured to communicate with an endpoint 115 in a media session using the Service Function Chaining system 100. Endpoints 110 and/or 115 may include, for example, smart phones, tablets, laptop computers, desktop computers, virtual machine applications running in a datacenter, or other types of computing devices with multimedia capabilities. The media session from endpoint 110 enters the system 100 at a classifier node 120 that includes media session logic 125. The system 100 also includes Service Function Forwarders (SFF) 130, 132, and 134 as (physical or virtual) network elements to direct the media session streams to various service functions. SFF 130 is coupled to service functions 140 and 145, which may be multiple instances of the same service function, i.e., two SIP Proxy servers. Alternatively, service functions 140 and 145 may include two different service functions, i.e., a SIP Proxy server and a Session Border Controller.

Similarly, SFF 132 is coupled to service functions 150 and 155, and may direct media streams to those service functions based on the service function path and the session identifier carried in the Network Service Header. SFF 134 is coupled to service functions 160 and 165, which represent the final service functions in the service function path. After the last service function has been performed, the SFF 134 forwards the media streams to endpoint 115. In the example shown in FIG. 1, three SFF nodes are shown, each coupled to two service functions, but the techniques presented herein may be applied to Service Function Chaining systems with any number of SFF nodes and any number of service functions. Additional network elements, either inside the Service Function Chain system 100 or outside of the system 100 may also be included to transmit the flows between endpoint 110 and endpoint 115.

In one example, a conferencing server or Session Border Controller identifies 5-tuples (e.g., source address, source port, destination address, destination port, protocol) for any media streams associated with an offer/answer exchange. It then conveys the 5-tuple for each media stream and the associated session identifier for the media session to the classifier node 120. The classifier node 120 generates a Network Service Header (NSH) with metadata headers. For each media stream associated with a particular session, the classifier node 120 sets a metadata header to include the session identifier. In this way, subsequent service functions in the service function path may correlate all of the media streams associated with a particular media session. The classifier node 120 may gather the session identifier from the packets in the media stream itself, or as a result of the classification into a service function path.

In another example, media streams from multiple participants, e.g., participants in a conference call, may be assigned the same session identifier. One or more classifier nodes, e.g., classifier node 120, may encode the same session identifier into the NSH for each media stream to ensure that they are grouped together at a Media Distribution Device (MDD) responsible for the conference call.

In a further example, the NSH may be a variable length, Type 2 NSH, with a specific vendor type (e.g., Cisco), and an Intermediary-safe SIP session ID (INSIPID) with a reserved type (e.g., type 71). The metadata header that includes the session identifier may have the form:

Referring now to FIG. 2, a simplified block diagram is shown of a classifier network device 120 configured to perform the techniques of a classifier node. Classifier 120 includes, among other possible components, a processor 210 to process instructions relevant to processing communication packets for a Service Function Chain system, and memory 220 to store a variety of data and software instructions (e.g., Classification logic 230, Media Session logic 125, communication packets, etc.). The classifier 120 also includes a network processor application specific integrated circuit (ASIC) 240 to process communication packets that flow through the classifier device 120. Network processor ASIC 240 processes communication packets be sent to and received from ports 250, 251, 252, 253, 254, and 255. While only six ports are shown in this example, any number of ports may be included in classifier device 120.

Memory 220 may include read only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical/tangible (e.g., non-transitory) memory storage devices. The processor 210 is, for example, a microprocessor or microcontroller that executes instructions for implementing the processes described herein. Thus, in general, the memory 220 may comprise one or more tangible (non-transitory) computer readable storage media (e.g., a memory device) encoded with software comprising computer executable instructions and when the software is executed (e.g., by the processor 210) it is operable to perform the operations described herein.

It is to be understood that the classifier network device may be a physical device or a virtual (software) device. In the latter case, the classifier network device is embodied as software running on a compute node (e.g., in a datacenter or other environment) through which traffic for determining how to be routed into a Service Function Chain.

Referring now to FIG. 3, a simplified block diagram shows flows being routed from endpoint 110 to endpoint 115 through service functions based on a media session identifier. The classifier node 120 receives a packet from signaling flow 310 of a media session and determines a session identifier to associate with the media session. The classifier node 120 encapsulates the flow 310 with a Network Service Header and includes the session identifier in a metadata header of the Network Service Header. The signaling flow 310 is directed to a service function path that includes two service functions, such as a SIP proxy service function followed by a Session Border Control service function.

The SFF node 130 sends the signaling flow 310 to SIP Proxy 145 which generates signaling flow 312. The SFF node 130 forwards the signaling flow 312 to the next SFF node 132 in the service function path. The SFF node 132 sends the signaling flow 312 to the Session Border Controller 150, which generates a signaling flow 314. Since the Session Border Controller 150 is the final service function, the SFF node 132 removes the Network Service Header and forwards the signaling flow 314 to the endpoint 115.

The classifier node 120 also receives a media flow 320 from the endpoint 110 and determines that it is part of the same media session as the signaling flow 310. The classifier node 120 encapsulates the media flow 320 with a Network Service Header and includes the same session identifier in a metadata header of the Network Service Header. The media flow 320 is directed to a service function path that includes a service function, such as a Session Border Control service function.

The SFF node 132 sends the media flow 320 to the Session Border Controller 150. In one example, the SFF node 132 reads the session identifier in the Network Service Header, and sends any flows with the same session identifier to the same instance of the service function, e.g., Session Border Controller 150. This ensures that the same instance of each service function captures all of the flows associated with a particular media session. The Session Border Controller 150 generates media flow 325 and returns it to the SFF node 132. The SFF node 132 forwards the media flow 325 to the endpoint 115. In one example, the media flow may be part of a media session that is being recorded, and the Session Border Controller also generates a media flow 330, which is directed to a session recording service function. The media flow 330 is forwarded by SFF node 134 to the session recording server 165, where the session is recorded.

In FIG. 3, only one direction of data streaming is shown, i.e., from endpoint 110 to endpoint 115. However, media sessions may be bidirectional and include flows in both directions, such as from endpoint 115 to endpoint 110. Each stream will pass through a classifier node that will encapsulate the packets in the stream with a Network Service Header including a session identifier associated with the media session. In general, any streams to and/or from any number of endpoints may use the techniques presented herein to pass the session identifier to any service function in the service function path.

In one example, the session identifier may be used to help identify media sessions across separate call legs, such as flow 320 between the endpoint 110 and the Session Border Controller 150, and flow 325 between the Session Border Controller 150 and the endpoint 115. The session identifier carried in the Network Service Header may also be used to correlate flows across SIP Proxy 145, Session Border Controller 150, and session recording server 165.

In another example, the session identifier may be used to make decisions regarding service functions, such as selecting which service function to apply to particular media sessions. An entity, such as a Software Defined Network controller 340 may dynamically program classifier node 120 to alter and/or extend a service function path for specific sessions based on the session identifier. For instance, the classifier node 120 may be dynamically programmed to record only desired media sessions based on the session identifiers and selectively invoke the session recording service function. Similarly, the recording of the specific media sessions may be dynamically stopped at the request of the controller. This may be especially useful when users start/stop recording a media session midway through the session.

In a further example, the session identifiers may be used by the service functions to send statistics to a flow collector for various purposes, e.g., auditing, performance monitoring. The session identifiers would provide a common element to aggregate and summarize flows for media sessions across all of the separate legs of the flows.

Referring now to FIG. 4, a simplified block diagram shows media flows being selectively routed to different service functions based on session identifiers. In some cases, end-to-end session identifiers may be grouped or split to provide finer or coarser media stream granularity, as part of the classification done in the classifier node 120. The classifier 120 receives a video stream 410 and an audio stream 420 from endpoint 110. The video stream 410 and audio stream 420 belong to the same media session, and are initially encapsulated with the same session identifier in the Network Service Header. The service function paths associated with each stream include a Session Border Controller 150, which generates video stream 415 and audio stream 425 to send to the endpoint 115.

In one example, a user wants to record the audio of the media session, but not the video. The classifier node 120 may split the session identifier and create a new session identifier for the audio stream 420, encapsulating the audio stream 420 with a new Network Service Header. The new session identifier causes the Session Border Controller 150 to generate an audio stream 430 which is sent to the session recording server 165. The session recording server 165 records the audio stream 430 with the new session identifier, while the audio stream 425 and video stream 415 are sent to the endpoint 115 with the original session identifier. In other terms, the original session identifier may be referred to as a “first session identifier” and the new session identifier may be referred to as a “second session identifier”. Likewise, the original Network Service Header may be referred to as a “first network service header” and the new Network Service Header may be referred to as a “second network service header”.

Referring now to FIG. 5, a flowchart is shown for a process 500 by which a classifier node (classifier) inserts a media session identifier into the Network Service Header according to one example. In step 510, the classifier receives a media stream from a first endpoint. The media stream is part of a media session between the first endpoint and at least one other endpoint. In step 520, the classifier determines a service function path for the media stream. The service function path comprises an ordered list of service functions that will act on the media stream. In step 530, the classifier determines a session identifier (e.g., Session-ID) for the media session. The session identifier may be determined by information in packets of the media stream. Alternatively, the classifier may generate the session identifier based on the classification of the packets in the media stream.

In step 540, the classifier encapsulates the media stream with a Network Service Header that specifies the service function path that the media stream will take. The Network Service Header includes one or more metadata headers, one of which will include the session identifier. The metadata headers may be variable or fixed length, and may be formatted according to MetaData (MD) Type 1 or MD Type 2 headers. After the media stream is encapsulated with a Network Service Header, each of the service functions in the service function path act on the media stream. Each of the service functions may use the session identifier in the Network Service Header to correlate other media streams in the same media session.

In summary, the techniques presented herein leverage the Network Service Header to propagate end-to-end session identifiers for use in multimedia communication systems. This allows for media-session-based application of service, and multimedia sub- or super-media flow reclassification and branching. These techniques identify and correlate sessions in multimedia systems using metadata available in-band with the Network Service Header. This mechanism allows a communication system design that does not rely on a complex mechanism to convey session identifiers to all of the relevant service functions that may be able to use the session identifier. Further, the Network Service Header session identifier may be applied to media streams for protocols that have not defined an end-to-end session identifier. This allows for media-session-based logging and tracing, as well as application of intelligent services at mid-points in the service function path. Additionally, the techniques presented herein enable flexible granularity in processing media flows by grouping and splitting media flows according to session identifiers.

In one form, the techniques presented herein provide for a computer-implemented method performed at a classifier node for a service function chain, the method including receiving a media stream from a first endpoint device. The media stream is associated with a media session between the first endpoint device and at least a second endpoint device. The classifier node determines a service function path for the media stream. The service function path comprises an ordered list of service functions to process the media stream. The classifier node determines a session identifier for the media session and encapsulates the media stream with a Network Service Header. The Network Service Header comprises an indication of the service function path and a metadata header with the session identifier.

In another form, the techniques presented herein provide for an apparatus comprising a network interface unit and a processor. The network interface unit is configured to communicate with a plurality of (physical or virtual) network devices having one or more service functions that are part of a service function chain, and a first endpoint device. The processor is configured to receive, via the network interface unit, a media stream from the first endpoint. The media stream is associated with a media session between the first endpoint and at least a second endpoint. The processor is configured to determine a service function path for the media stream. The service function path comprises an ordered list of service functions to process the media stream. The processor is configured to determine a session identifier for the media session and encapsulate the media stream with a Network Service Header. The Network Service Header comprises an indication of the service function path and a metadata header with the session identifier.

In yet another form, the techniques presented herein provide for a non-transitory computer readable storage media encoded with software comprising computer executable instructions. When the software is executed, the instructions are operable to cause a processor to receive a media stream from a first endpoint. The media stream is associated with a media session between the first endpoint and at least a second endpoint. The instructions cause the processor to determine a service function path for the media stream. The service function path comprises an ordered list of service functions to process the media stream. The instructions cause the processor to determine a session identifier for the media stream and encapsulate the media stream with a Network Service Header. The Network Service Header comprises an indication of the service function path and a metadata header with the session identifier.

The above description is intended by way of example only. Various modifications and structural changes may be made therein without departing from the scope of the concepts described herein and within the scope and range of equivalents of the claims. 

What is claimed is:
 1. A method comprising: receiving at a classifier node, a media stream from a first endpoint, the media stream associated with a media session between the first endpoint and at least a second endpoint; determining a service function path for the media stream, the service function path comprising an ordered list of service functions to process the media stream; determining a session identifier for the media session; and encapsulating the media stream with a network service header, the network service header comprising an indication of the service function path and a metadata header with the session identifier.
 2. The method of claim 1, further comprising forwarding the encapsulated media stream to a first service function in the service function path.
 3. The method of claim 1, further comprising: receiving at the classifier node, one or more additional media streams associated with the media session; and encapsulating at least one of the additional media streams with the network service header including the session identifier for the media session.
 4. The method of claim 3, further comprising encapsulating at least one of the additional media streams with a new network service header, the new network service header including a new session identifier different than the first session identifier.
 5. The method of claim 3, further comprising: receiving one or more different media streams associated with a different media session; and encapsulating the one or more different media streams with the network service header including the session identifier.
 6. The method of claim 1, further comprising: receiving an indication to change the service function path for media streams associated the media session to an updated service function path; and encapsulating the media stream with an updated network service header, the updated network service header comprising an indication of the updated service function path and the metadata header with the session identifier.
 7. The method of claim 6, wherein the updated service function path includes a session recording service function to record the media session.
 8. An apparatus comprising: a network interface unit configured to communicate with a plurality of network devices and a first endpoint; a processor configured to: receive, via the network interface unit, a media stream from the first endpoint, the media stream associated with a media session between the first endpoint and at least a second endpoint; determine a service function path for the media stream, the service function path comprising an ordered list of service functions to process the media stream; determine a session identifier for the media session; and encapsulate the media stream with a network service header, the network service header comprising an indication of the service function path and a metadata header with the session identifier.
 9. The apparatus of claim 8, wherein the processor is further configured to forward the encapsulated media stream, via the network interface unit, to a first service function in the service function path.
 10. The apparatus of claim 8, wherein the processor is further configured to: receive, via the network interface unit, one or more additional media streams associated with the media session; and encapsulate at least one of the additional media streams with the network service header including the session identifier for the media session.
 11. The apparatus of claim 10, wherein the processor is further configured to encapsulate at least one of the additional media streams with a new network service header, the new network service header including a new session identifier different than the first session identifier.
 12. The apparatus of claim 10, wherein the processor is further configured to: receive, via the network interface unit, one or more different media streams associated with a different media session; and encapsulate the one or more different media streams with the network service header including the session identifier.
 13. The apparatus of claim 8, wherein the processor is further configured to: receive an indication to change the service function path for media streams associated the media session to an updated service function path; and encapsulate the media stream with an updated network service header, the updated network service header comprising an indication of the updated service function path and the metadata header with the session identifier.
 14. The apparatus of claim 13, wherein the updated service function path includes a session recording service function to record the media session.
 15. One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to cause a processor to: receive a media stream from a first endpoint, the media stream associated with a media session between the first endpoint and at least a second endpoint; determine a service function path for the media stream, the service function path comprising an ordered list of service functions to process the media stream; determine a session identifier for the media session; and encapsulate the media stream with a network service header, the network service header comprising an indication of the service function path and a metadata header with the session identifier.
 16. The computer readable storage media of claim 15, wherein the instructions further cause the processor to forward the encapsulated media stream to a first service function in the service function path.
 17. The computer readable storage media of claim 15, wherein the instructions further cause the processor to: receive one or more additional media streams associated with the media session; and encapsulate at least one of the additional media streams with the network service header including the session identifier for the media session.
 18. The computer readable storage media of claim 17, wherein the instructions further cause the processor to encapsulate at least one of the additional media streams with a new network service header, the new network service header including a new session identifier different than the first session identifier.
 19. The computer readable storage media of claim 17, wherein instructions further cause the processor to: receive one or more different media streams associated with a different media session; and encapsulate the one or more different media streams with the network service header including the session identifier.
 20. The computer readable storage media of claim 17, wherein the instructions further cause the processor to: receive an indication to change the service function path for media streams associated the media session to an updated service function path, the updated service function path including a session recording service function to record the media session; and encapsulate the media stream with an updated network service header, the updated network service header comprising an indication of the updated service function path and the metadata header with the session identifier. 